Chlorine Lock? Draining pool only option?

[BigDave]

I see your post.

There's no such thing as chlorine lock but your CYA is very high. I'd guess as a result of use of tablets. You can run a pool with high CYA, there has been some discussion on this subject here on the forum. Have you read through Ben's Best Guess Chart?

Another note: We don't put much stock in pool store chemistry test - there's alot of reasons but suffice it to say that they are often misleading. We recommend the Taylor K-2006 kit for reliable testing.

[PoolDoc]

Without a DPD drop-count chlorine test, like the Taylor K2006, you will not be able to manage the appropriate chlorine levels for a CYA = 195 (or anything in that range).

Also, the 2006 has relatively accurate CYA testing -- still not VERY accurate, but test strips are TERRIBLE for measuring CYA, even when read electronically. If you actually have CYA = 195, you'll have to drain 75% just to get down to a CYA = 50 ppm.

Get some polyquat -- it will get the pool from turning green, and get a K2006. Test your CYA with it, and then decide what to do.